The operator could not recall the course to steer indicated by the DGPS unit on passing the east channel buoys but a course directly to the Scarborough marina from that vicinity does not clear the eastern extension of Outer Harbour East Headland. As a minimum, the vessel would have had to alter course at a waypoint south and east of the eastern extension to clear that point of land and safely proceed to a position off Bluffers Park marina. The operator displayed a degree of compliance with the basic tenets of 'Bridge Resource Management' when he altered course to starboard at the suggestion of the crewmember. The crewmember's concern over the vessel's position which prompted the suggestion did not manifest itself in any further advice and the operator was not influenced to reduce speed or take any other measures to determine if the TIMEOUT was standing into danger. The TIME OUT was equipped with a depth sounder and a spotlight, two pieces of equipment which had the potential to be useful to the operator. The operator did not use the depth sounder because of the reported visual distraction of the instrument's lighting. Information gathered at the site indicated that the echo sounder would likely have contributed little in preventing the accident on a vessel travelling at 24 knots. The nature of the land fill slope at the shore line is steep, and, with the vessel closing at 12.5m/sec there would be little reaction time left to the operator when shelving began. The hazy atmosphere and other impediments to forward visibility that the operator was experiencing, make it difficult to determine whether or not the spotlight would have been effective in a vessel proceeding at high speed. Certainly, if the TIMEOUT had been stopped, or even if the speed had been reduced, the spotlight was a useful piece of equipment to assist in the vessel's navigation. Although the vessel was a total constructive loss as a result of striking the material which made up the shore (broken concrete slabs with metal projections and rocks) the damage to the vessel and the nature of the injuries to those on board was lessened because the vessel was deflected upwards after first striking a submerged rock.Analysis The operator could not recall the course to steer indicated by the DGPS unit on passing the east channel buoys but a course directly to the Scarborough marina from that vicinity does not clear the eastern extension of Outer Harbour East Headland. As a minimum, the vessel would have had to alter course at a waypoint south and east of the eastern extension to clear that point of land and safely proceed to a position off Bluffers Park marina. The operator displayed a degree of compliance with the basic tenets of 'Bridge Resource Management' when he altered course to starboard at the suggestion of the crewmember. The crewmember's concern over the vessel's position which prompted the suggestion did not manifest itself in any further advice and the operator was not influenced to reduce speed or take any other measures to determine if the TIMEOUT was standing into danger. The TIME OUT was equipped with a depth sounder and a spotlight, two pieces of equipment which had the potential to be useful to the operator. The operator did not use the depth sounder because of the reported visual distraction of the instrument's lighting. Information gathered at the site indicated that the echo sounder would likely have contributed little in preventing the accident on a vessel travelling at 24 knots. The nature of the land fill slope at the shore line is steep, and, with the vessel closing at 12.5m/sec there would be little reaction time left to the operator when shelving began. The hazy atmosphere and other impediments to forward visibility that the operator was experiencing, make it difficult to determine whether or not the spotlight would have been effective in a vessel proceeding at high speed. Certainly, if the TIMEOUT had been stopped, or even if the speed had been reduced, the spotlight was a useful piece of equipment to assist in the vessel's navigation. Although the vessel was a total constructive loss as a result of striking the material which made up the shore (broken concrete slabs with metal projections and rocks) the damage to the vessel and the nature of the injuries to those on board was lessened because the vessel was deflected upwards after first striking a submerged rock. The passage from Ontario Place to Scarborough was undertaken during the hours of darkness using only a DGPS unit to supplement visual navigation. Airborne residue from the fireworks display and back scatter of lights in the windshield adversely affected the operator's forward vision. Despite uncertainty on the part of the operator and the crew member regarding the position of the TIMEOUT, the vessel's high planing speed was not slackened. The usefulness of other navigational equipment on the vessel was diminished because speed was not reduced to assess the vessel's situation. The vessel was prematurely brought on to a course for the home marina without having made sufficient easting to clear the eastern extension of the Outer Harbour East Headland. The light on the eastern extension of the Outer Harbour East Headland is markedly less conspicuous than that on the western extension and, on different approaches, it was obscured by vegetation when navigating within 220 m of the shore.Findings The passage from Ontario Place to Scarborough was undertaken during the hours of darkness using only a DGPS unit to supplement visual navigation. Airborne residue from the fireworks display and back scatter of lights in the windshield adversely affected the operator's forward vision. Despite uncertainty on the part of the operator and the crew member regarding the position of the TIMEOUT, the vessel's high planing speed was not slackened. The usefulness of other navigational equipment on the vessel was diminished because speed was not reduced to assess the vessel's situation. The vessel was prematurely brought on to a course for the home marina without having made sufficient easting to clear the eastern extension of the Outer Harbour East Headland. The light on the eastern extension of the Outer Harbour East Headland is markedly less conspicuous than that on the western extension and, on different approaches, it was obscured by vegetation when navigating within 220 m of the shore. TheTIMEOUT ran aground on the Outer Harbour East Headland because the course was set for Bluffers Park marina before the vessel had cleared the eastern extension of the peninsula. Contributing factors to the occurrence were that speed was not reduced when there was uncertainty regarding the vessel's position and that the operator's visibility was impaired by the back scatter of lights in the windshield and by smoke from the fireworks display suspended in the humid atmosphere.Causes and Contributing Factors TheTIMEOUT ran aground on the Outer Harbour East Headland because the course was set for Bluffers Park marina before the vessel had cleared the eastern extension of the peninsula. Contributing factors to the occurrence were that speed was not reduced when there was uncertainty regarding the vessel's position and that the operator's visibility was impaired by the back scatter of lights in the windshield and by smoke from the fireworks display suspended in the humid atmosphere.